FIELD ASSESSMENT PROBLEMS. THE DIFFUSION OF POLYDISPERSE PARTICULATE CLOUDS

Abstract

Separation of particles released in the atmosphere is due to small scale turbulence and varying terminal velocity of the particles. The distribution of particles downwind, which satisfies the differential equation of turbulent diffusion, is obtained by numerical integration when the distribution of terminal velocity is lognormal. The non-dimensional ground deposition depends only on the logarithm of the ratio of the median terminal velocity to the friction velocity, and on the coefficient of variation of the terminal velocity distribution. An analytic approximation is obtained, which is quite good for a wide range of basic parameters. Another approximation is used which neglects the variation of terminal elocity. This procedure is reasonable for a much smaller range of basic parameters. Application to a diabatic atmosphere is also given.

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Document Details

Document Type
Technical Report
Publication Date
Nov 15, 1961
Accession Number
AD0269560

Entities

People

  • Ben Davidson
  • Leon Herbach

Organizations

  • New York University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Adiabatic Conditions
  • Arithmetic
  • Atmospheres
  • Coefficients
  • Diffusion
  • Diffusion Coefficient
  • Equations
  • Government Procurement
  • New York
  • Numerical Integration
  • Particle Size
  • Particles
  • Particulates
  • Standards
  • Turbulent Diffusion
  • Universities
  • Wind

Readers

  • Aerosol Science/Aerosol Physics
  • Combustion and Flow Dynamics.
  • Statistical inference.